Muscular: 05 Vanessa Martinez 10/14/21 Period 1 - Coggle Diagram
Muscular: 05 Vanessa Martinez
Epimysium: dense irregular CT surrounds entire muscle
Perimysium: fibrous CT surrounding each muscle fiber
Endomysium: fine areolar CT surrounding each muscle fiber
duchenne muscular dystrophy: very
common and serious
; destroys muscles and it appears in childhood
name of all skeletal muscles
trapezius•Sternocleidomastoid•deltoid •pectoralis major•serratus anterior•bicep brachii •tricep brachii•Brachioradialis •Flexor carpi radialis •rectus abdominis•external oblique•infraspinatus•teres major•latissimus dorsi •extensor carpi radialis•flexor carpi ulnaris •extensor digitorum
•iliopsoas•adductor longus•sartorius•gracilis•rectus femoris•vastus lateralis•vastus medialis •bicep femoris•semitendinosus•semimembranosus tibialis anterior •extensor digitorum longus•fibularis longus•gastrocnemius•soleus
is inside the myofibrils, composed with thick(myosin) and thin (actin) filaments. When contracted, thick filament pulls on thin filaments together. when it is relaxed, thin filament goes back to its original shape.
are scattered through muscle fibers that supply energy( ATP) that is needed for muscle contraction. there are 2 transport systems within the muscle:
which runs parallel to
and transverse tubules, which runs perpendicular to filament. the entire muscle fiber is surrounded with a membrance called
major functions of the muscular system
skeletal muscles are stimulated by somatic motor neuron.
-Axons travel from central nervous to skeletal uscle
each axon divided into branches forming the
AP arrives @ axon terminal
Voltage- gated calcium channels open, calcium enters motor neurons.
calcium entry causes release of Ach neurotransmitter into synpatic cleft.
ACH diffuses across to ACh receptors on sarcolemma
ACh binding to receptors, open gates allowing Na to enter resulting in end plate potential
Acetylcholinesterase degrades ACh
Three types of muscles & their functions
: attaches to bones to skin. they are composed of myofibrils of sacromeres.
: endomysium. is NOT composed of myofibrils but has actin and myosin filaments.
: endomysium attached to fibrous skeleton of heart. They are composed of myofibirls but of irregular thickness.
action potential in a muscle fiber
electrical signal that can travel along a cell membrane as a wave
sliding filament theory
This explains how muscle contracts based on how muscle fibers (actin and myosin) slide against each other to generate tension in the overall muscle.
It all starts with the brain where signals are sent along the motor neuron. within this motor neuron are vesicles that contain neurotransmitter, acetylcholine. This reaches the receptors on the muscle sarcolemma which causes an impulse.
this impulse then travels down the membrane an to the t- tubules. which causes calcium to be released from the sarcoplasmic reticulum.
3.calcium binds to the structure on the actin which causes its shape to change.
this shape allows myosin heads to form
between the actin and the myosin
ATP is created and the actin filament slides inward and shortens or contracts the whole muscle.